Tendermint software is empowering the Cosmos ecosystem and holds billions of value worldwide. Its main goal is providing BFT POS consensus engine/service for anyone to build custom blockchains on top. The software accomplishes the goal good enough together with Cosmos SDK.
As everything in our world, nothing is perfect, and Tendermint is not an exception. Particularly, it's far from that point. It has been in development for many years(8 from the moment of writing) and haven't seen any bottom to top revisions for too long. Recently, a ray of light broke through and there was an attempt to do such a revision for the bottom layer of the stack - p2p networking, opening possibility for more pervasive improvements.
But..., it was a complete failure and PITA for teams trying to use it. As a result, the failed attempt prompted lots of internal drama, which in the end makes all the involved stakeholders even more conservative to drastic changes like this, tightening nuts for any fundamental revisions that the software starves for. Bags are full(of comfort obviously) so why would anyone need to risk?
Regret it or not, but the poor decisions on the lower level of the stack affect the whole stack built or not, no matter what tech it is. The stack over Tendermint's legacy blooms and flourishes(Cosmos SDK, IBC, IgniteCLI, Gno), millions are invested in the ecosystem to buidl, to build over ABCI(++).
TBC
Stands for If Only Tendermint Was A Library and it's goal is to overhaul Tendermint software. Make it lightweight, performant, modular and composable.